Maybe it's time for you dabble in a new genre. Just about all of my games are pretty low intensity. Racing games and fighting games can be pretty involved and deep, but the great thing about them is that you don't have to do the career mode or story mode if you don't have the time or inclination to.

I've also just gotten Nation Red (I believe it's available on Steam as well). It plays like Asteroids, except with the great graphics and ZOMBIES!